Detection method, device and system of switching power amplifier, medium and product

Abstract

The invention discloses a fault detection method and device for a switching power amplifier, a magnetic bearing controller, a magnetic bearing system, a storage medium and a computer program product, and the method comprises the steps: in the operation process of the switching power amplifier, in the current switching period of the switching power amplifier, according to a set sampling frequency, carrying out fault detection on the switching power amplifier; the current detection value of the first bridge arm, the current detection value of the second bridge arm and the coil current of the magnetic bearing controlled by the magnetic bearing controller are obtained; according to the current detection value of the first bridge arm, the current detection value of the second bridge arm and the coil current of the magnetic bearing, whether the switching power amplifier breaks down or not is determined, and fault detection of the switching power amplifier is achieved. According to the scheme, whether the switching power amplifier breaks down or not is determined according to the current detection value of the first bridge arm, the current detection value of the second bridge arm, the set sampling frequency and the set switching period, online fault detection of the switching power amplifier is achieved, and the troubleshooting efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of magnetic bearing technology, specifically relating to a fault detection method, device, magnetic bearing controller, magnetic bearing system, storage medium, and computer program product for a switching power amplifier, and particularly to a fault detection method, device, magnetic bearing controller, magnetic bearing system, storage medium, and computer program product for a switching power amplifier in a magnetic bearing controller. Background Technology

[0002] Electromagnetic bearings (i.e., magnetic levitation bearings) are a new type of contactless support bearing that uses electromagnets to generate controllable electromagnetic force to levitate a rotor. A magnetic levitation bearing control system (i.e., a magnetic bearing controller) generally consists of three parts: a main controller, a switching power amplifier, and a displacement sensor. The rotor position of the magnetic bearing (i.e., the magnetic levitation bearing) is detected by the displacement sensor. The main controller outputs a corresponding current control signal based on the deviation between the real-time rotor position and the reference position. The switching power amplifier outputs current based on the current control signal to control the rotor and maintain its levitation state.

[0003] As one of the core components of the magnetic bearing controller, the switching power amplifier may fail due to the magnetic bearing operating in a harsh environment. However, fault detection of the switching power amplifier is quite difficult.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a fault detection method, device, magnetic bearing controller, magnetic bearing system, storage medium, and computer program product for a switching power amplifier. This addresses the problem that fault detection of the switching power amplifier in a magnetic bearing controller may occur when the magnetic bearing operates in harsh environments, but the fault detection of the switching power amplifier is difficult. The invention achieves the effect of determining whether the switching power amplifier is faulty by using the current detection values ​​of the first bridge arm and the second bridge arm, setting the sampling frequency, and setting the switching period. This enables online fault detection of the switching power amplifier and improves the efficiency of fault diagnosis.

[0006] This invention provides a fault detection method for a switching power amplifier, applicable to a magnetic bearing controller. The switching power amplifier includes an H-bridge, which has a first bridge arm and a second bridge arm. The first bridge arm has a first switching transistor, and the second bridge arm has a second switching transistor. The fault detection method for the switching power amplifier includes: during the operation of the switching power amplifier, within the current switching cycle of the switching power amplifier, acquiring the current detection value of the first bridge arm, acquiring the current detection value of the second bridge arm, and acquiring the coil current of the magnetic bearing controlled by the magnetic bearing controller at a set sampling frequency; determining whether the switching power amplifier has malfunctioned based on the current detection values ​​of the first bridge arm, the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, thereby achieving fault detection of the switching power amplifier.

[0007] In some embodiments, a first sampling resistor module is provided between the grounding terminal of the first bridge arm and ground; a second sampling resistor module is provided between the grounding terminal of the second bridge arm and ground; and the resistance values ​​of the first and second sampling resistor modules are the same as the resistance value of the coil of the magnetic bearing; obtaining the current detection value of the first bridge arm includes: obtaining a voltage value sampled by the first sampling resistor module to characterize the current detection result of the first bridge arm, as the current detection value of the first bridge arm; obtaining the current detection value of the second bridge arm includes: obtaining a voltage value sampled by the second sampling resistor module to characterize the current detection result of the second bridge arm, as the current detection value of the second bridge arm.

[0008] In some implementations, determining whether the switching power amplifier is faulty based on the current detection values ​​of the first bridge arm, the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller includes: determining the sum of the current detection values ​​of the first bridge arm, denoted as the total current detection value of the first bridge arm, based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm; determining the sum of the current detection values ​​of the second bridge arm, denoted as the total current detection value of the second bridge arm, based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm; and determining the current threshold of the switching power amplifier based on the switching period of the switching power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller. The system determines whether the following conditions are met: the total current detection value of the first bridge arm is 0 or the total current detection value of the first bridge arm is equal to the current threshold of the switching power amplifier, and the total current detection value of the second bridge arm is 0 or the total current detection value of the second bridge arm is equal to the current threshold of the switching power amplifier; if the conditions are met, the switching power amplifier is determined to be faulty, and a reminder message indicating the fault location and / or fault type of the switching power amplifier is output; if the conditions are not met, the switching power amplifier is determined not to be faulty, and the switching power amplifier continues to operate, then returns to the previous cycle of the switching power amplifier to obtain the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller at the set sampling frequency.

[0009] In some embodiments, determining the sum of the current detection values ​​of the first bridge arm, based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm, and denoting it as the total current detection value of the first bridge arm, includes: taking the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm as the sum of the current detection values ​​of the first bridge arm, and denoting it as the total current detection value of the first bridge arm; and / or, determining the sum of the current detection values ​​of the second bridge arm, based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm, and denoting it as the current detection value of the second bridge arm. The total value includes: taking the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm as the sum of the current detection values ​​of the second bridge arm, and recording it as the total current detection value of the second bridge arm; and / or, determining the current threshold of the switching power amplifier based on the switching period of the switching power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, including: taking the product of the switching period of the switching power amplifier, the set sampling frequency, the coil current of the magnetic bearing controlled by the magnetic bearing controller, and the coil resistance of the magnetic bearing controlled by the magnetic bearing controller as the current threshold of the switching power amplifier.

[0010] In some implementations, determining that the switching power amplifier has malfunctioned and outputting an alert message indicating the fault location and / or fault type of the switching power amplifier includes: if the total current detected in the first bridge arm is determined to be 0, then a short-circuit fault is determined in the first switching transistor, and an alert message indicating the fault location of the switching power amplifier is the position of the first switching transistor and / or the fault type of the switching power amplifier is a short-circuit fault is output; if the total current detected in the first bridge arm is determined to be equal to the current threshold of the switching power amplifier, then an open-circuit fault is determined in the first switching transistor, and an alert message indicating the fault location of the switching power amplifier is the position of the first switching transistor and / or the fault type of the switching power amplifier is a short-circuit fault is output; The system outputs an alert message indicating that the location of the switch transistor and / or the fault type of the switching power amplifier is an open-circuit fault. If the total current detection value of the second bridge arm is determined to be 0, then an open-circuit fault is determined to have occurred in the second switch transistor, and an alert message indicating that the fault location of the switching power amplifier is the location of the second switch transistor and / or the fault type of the switching power amplifier is an open-circuit fault is output. If the total current detection value of the second bridge arm is determined to be equal to the current threshold of the switching power amplifier, then a short-circuit fault is determined to have occurred in the second switch transistor, and an alert message indicating that the fault location of the switching power amplifier is the location of the second switch transistor and / or the fault type of the switching power amplifier is a short-circuit fault is output.

[0011] In conjunction with the above method, another aspect of the present invention provides a fault detection device for a switching power amplifier, applicable to a magnetic bearing controller; the switching power amplifier includes an H-bridge, the H-bridge having a first bridge arm and a second bridge arm, the first bridge arm having a first switching transistor, and the second bridge arm having a second switching transistor; the fault detection device for the switching power amplifier includes: an acquisition unit configured to, during the operation of the switching power amplifier, within the current switching cycle of the switching power amplifier, acquire the current detection value of the first bridge arm, acquire the current detection value of the second bridge arm, and acquire the coil current of the magnetic bearing controlled by the magnetic bearing controller at a set sampling frequency; and a control unit configured to determine whether the switching power amplifier has malfunctioned based on the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, thereby realizing fault detection of the switching power amplifier.

[0012] In some embodiments, a first sampling resistor module is provided between the grounding terminal of the first bridge arm and ground; a second sampling resistor module is provided between the grounding terminal of the second bridge arm and ground; and the resistance values ​​of the first and second sampling resistor modules are the same as the resistance value of the coil of the magnetic bearing; the acquisition unit acquires the current detection value of the first bridge arm by: acquiring a voltage value sampled by the first sampling resistor module to characterize the current detection result of the first bridge arm, as the current detection value of the first bridge arm; the acquisition unit acquires the current detection value of the second bridge arm by: acquiring a voltage value sampled by the second sampling resistor module to characterize the current detection result of the second bridge arm, as the current detection value of the second bridge arm.

[0013] In some embodiments, the control unit determines whether the switching power amplifier has malfunctioned based on the current detection values ​​of the first bridge arm, the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller. This includes: determining the sum of the current detection values ​​of the first bridge arm, denoted as the total current detection value of the first bridge arm, based on the switching cycle of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm; determining the sum of the current detection values ​​of the second bridge arm, denoted as the total current detection value of the second bridge arm, based on the switching cycle of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm; and determining the fault status of the switching power amplifier based on the switching cycle of the switching power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller. The current threshold is determined; it is determined whether the total current detection value of the first bridge arm is 0 or the total current detection value of the first bridge arm is equal to the current threshold of the switching power amplifier, and the total current detection value of the second bridge arm is 0 or the total current detection value of the second bridge arm is equal to the current threshold of the switching power amplifier; if it is determined that the conditions are met, it is determined that the switching power amplifier has failed, and an alert message indicating the fault location and / or fault type of the switching power amplifier is output; if it is determined that the conditions are not met, it is determined that the switching power amplifier has not failed, and the operation of the switching power amplifier continues, and then returns to the previous switching cycle of the switching power amplifier to obtain the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller at the set sampling frequency.

[0014] In some embodiments, the control unit determines the sum of the current detection values ​​of the first bridge arm based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm, and records it as the total current detection value of the first bridge arm. This includes: taking the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm as the sum of the current detection values ​​of the first bridge arm, and recording it as the total current detection value of the first bridge arm; and / or, the control unit determines the sum of the current detection values ​​of the second bridge arm based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm, and records it as the total current detection value of the second bridge arm. The total current detection value includes: taking the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm as the sum of the current detection values ​​of the second bridge arm, and recording it as the total current detection value of the second bridge arm; and / or, the control unit determines the current threshold of the switching power amplifier based on the switching period of the switching power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, including: taking the product of the switching period of the switching power amplifier, the set sampling frequency, the coil current of the magnetic bearing controlled by the magnetic bearing controller, and the coil resistance of the magnetic bearing controlled by the magnetic bearing controller as the current threshold of the switching power amplifier.

[0015] In some embodiments, the control unit determines that the switching power amplifier has malfunctioned and outputs an alert message indicating the fault location and / or fault type of the switching power amplifier, including: if the total current detected in the first bridge arm is determined to be 0, then the first switching transistor is determined to have a short-circuit fault, and an alert message indicating the fault location of the switching power amplifier is the position of the first switching transistor and / or the fault type of the switching power amplifier is a short-circuit fault is output; if the total current detected in the first bridge arm is determined to be equal to the current threshold of the switching power amplifier, then the first switching transistor is determined to have an open .... The system provides an alert message indicating the location of the first switching transistor and / or the fault type of the switching power amplifier as an open-circuit fault. If the total current detection value of the second bridge arm is determined to be 0, an open-circuit fault is determined to have occurred in the second switching transistor, and an alert message indicating the fault location of the switching power amplifier as the location of the second switching transistor and / or the fault type of the switching power amplifier as an open-circuit fault is output. If the total current detection value of the second bridge arm is determined to be equal to the current threshold of the switching power amplifier, a short-circuit fault is determined to have occurred in the second switching transistor, and an alert message indicating the fault location of the switching power amplifier as the location of the second switching transistor and / or the fault type of the switching power amplifier as a short-circuit fault is output.

[0016] In conjunction with the above-described device, the present invention further provides a magnetic bearing controller, comprising: the fault detection device for the switching power amplifier described above.

[0017] In conjunction with the above-described device, the present invention further provides a magnetic bearing system, comprising: the fault detection device for the switching power amplifier described above, or the magnetic bearing controller described above.

[0018] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located executes the steps of the fault detection method for the switching power amplifier described above.

[0019] In conjunction with the above method, the present invention further provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the fault detection method for the switching power amplifier described above.

[0020] Therefore, the solution of the present invention addresses the switching power amplifier of a magnetic bearing controller. The switching power amplifier has an H-bridge, which has a first bridge arm (e.g., the left bridge arm) and a second bridge arm (e.g., the right bridge arm). The first bridge arm has a first switching transistor (e.g., switching transistor S1), and the second bridge arm has a second switching transistor (e.g., switching transistor S2). When fault detection of the switching power amplifier is required, within a set switching period (e.g., switching period Tk) of the H-bridge, the current detection value (e.g., voltage signal V) of the first bridge arm of the H-bridge is acquired at a set sampling frequency (e.g., sampling frequency fc). F1 ), and the current detection value of the second bridge arm (such as voltage signal V). F2 Based on the current detection values ​​of the first and second bridge arms, the set sampling frequency, and the set switching period, the system determines whether a fault has occurred in the switching power amplifier, such as whether a short circuit or open circuit fault has occurred in the first and second switching transistors, thus achieving fault detection of the switching power amplifier. Therefore, by determining whether a fault has occurred in the switching power amplifier based on the current detection values ​​of the first and second bridge arms, the set sampling frequency, and the set switching period, online fault detection of the switching power amplifier can be achieved, such as online determination of the fault point and fault type, improving fault diagnosis efficiency.

[0021] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of an embodiment of the fault detection method for a switching power amplifier of the present invention; Figure 2 This is a flowchart illustrating an embodiment of the method of the present invention for determining whether the switching power amplifier has malfunctioned; Figure 3 This is a schematic diagram of a structure of an embodiment of the fault detection device for the switching power amplifier of the present invention; Figure 4 This is a schematic diagram of the H-bridge circuit of a switching power amplifier. Figure 5 This is a schematic diagram of the fault detection circuit of the H-bridge circuit in a switching power amplifier. Figure 6 This is a schematic diagram of the current waveform of a three-level switching power amplifier; Figure 7 This is a schematic diagram of the control system for a switching power amplifier. Figure 8 This is a flowchart illustrating the fault detection method for the switching power amplifier in a magnetic bearing controller.

[0024] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows: 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] Considering that magnetic bearings operate in harsh environments, the switching power amplifier in the magnetic bearing controller may malfunction, but fault detection in switching power amplifiers is quite difficult. Common faults in the switching power amplifier of the magnetic bearing controller include short circuits and open circuits in the switching power devices. Accurately and quickly locating the fault point of the switching power amplifier is of great significance for rapidly repairing the power amplifier and efficiently restoring the normal operation of the magnetic bearing.

[0027] In the existing solutions, when a switching power amplifier fails, it needs to be replaced. A multimeter is then used to sequentially measure the continuity and voltage values ​​of the gate, source, and drain of each switching power device in the amplifier to determine which specific device is faulty. This method of troubleshooting is time-consuming and labor-intensive.

[0028] Therefore, the present invention proposes a fault detection method for a switching power amplifier, specifically a fault detection method for a switching power amplifier in a magnetic bearing controller. By analyzing the sum of the current sampling signal values ​​of each bridge arm and the fault type truth table, the fault location and fault type of the switching power device of the power amplifier can be determined. This method enables online determination of the fault point and fault type of the switching power amplifier, greatly improving the efficiency of fault diagnosis and reducing the time cost of fault repair.

[0029] According to embodiments of the present invention, a fault detection method for a switching power amplifier is provided, such as... Figure 1 The diagram shows a flowchart of an embodiment of the method of the present invention. This fault detection method for a switching power amplifier can be applied to a magnetic bearing controller; the switching power amplifier includes an H-bridge, the H-bridge having a first arm and a second arm, the first arm having a first switching transistor, and the second arm having a second switching transistor, wherein the first switching transistor is as follows... Figure 4 The switch S1 shown, the second switch as... Figure 5 The switch S2 shown is provided in this invention; the present invention proposes a fault detection circuit for a power amplifier switching power device. Figure 4 This is a schematic diagram of the H-bridge circuit of a switching power amplifier. (Example:) Figure 4 The switching power amplifier shown includes: switching transistors S1 and S2, diodes D1 and D2, resistor R0, and inductor L. Resistor R0 represents the resistive portion of the bearing coil, and inductor L represents the inductive portion of the magnetic bearing coil. Switches S1 and S2 are both power switching devices, such as MOSFETs and IGBTs. When both switching transistors S1 and S2 are MOSFETs, the DC power supply V... CC The source of the switching transistor S1 is connected to the drain of the switching transistor S1 and the cathode of the diode D1, respectively. The source of the switching transistor S1 is connected to the anode of the diode D1 via resistor R0 and inductor L. The switching transistor S1 is also connected to the cathode of the diode D2, and the anode of the diode D2 is grounded. The anode of the diode D1 is also connected to the drain of the switching transistor S2, and the source of the switching transistor S2 is grounded.

[0030] The magnetic bearing switching power amplifier (i.e., the switching power amplifier in the magnetic bearing controller) adopts the following... Figure 4 The diagram shows a half-bridge power topology using three-level modulation. With three-level modulation, the switching power amplifier will have three states: charging, freewheeling, and discharging. The freewheeling state is further subdivided into upward freewheeling and downward freewheeling: 1) Switches S1 and S2 are simultaneously turned on, and the bearing coil is in a charging state; 2) Switches S1 and S2 are simultaneously turned off, and the bearing coil is in a discharging state; 3) Switch S1 is turned on and switch S2 is turned off, and the bearing coil is in an upward freewheeling state; 4) Switch S1 is turned off and switch S2 is turned on, and the bearing coil is in a downward freewheeling state. In the solution of this invention, as... Figure 1 As shown, the fault detection method for the switching power amplifier includes steps S110 to S120.

[0031] In step S110, during the operation of the switching power amplifier, when fault detection of the switching power amplifier is required, within the current switching cycle of the switching power amplifier, the current detection value of the first bridge arm is acquired at a set sampling frequency, the current detection value of the second bridge arm is acquired, and the coil current of the magnetic bearing controlled by the magnetic bearing controller is acquired; wherein, the current detection value of the first bridge arm is as follows: Figure 5 The voltage signal V shown F1 The current detection signal of the second bridge arm is as follows: Figure 5 The voltage signal V shown F2The magnetic bearing controller controls the coil current of the magnetic bearing, such as the magnetic bearing coil current i.

[0032] In step S120, based on the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, it is determined whether the switching power amplifier has a fault, thereby realizing the fault detection of the switching power amplifier.

[0033] The present invention proposes a fault detection scheme for a magnetic bearing switching power amplifier. By using the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, the scheme determines whether the switching power amplifier has a fault, and judges the fault location and fault type of the switching power device of the power amplifier. This scheme enables online determination of the fault point and fault type of the switching power amplifier, greatly improving the efficiency of fault diagnosis and reducing the time cost of fault repair.

[0034] In some embodiments, a first sampling resistor module is provided between the grounding terminal of the first bridge arm and ground; a second sampling resistor module is provided between the grounding terminal of the second bridge arm and ground; and the resistance values ​​of both the first and second sampling resistor modules are the same as the resistance value of the coil of the magnetic bearing; wherein, the first sampling resistor module is as follows: Figure 5 The resistor R1 shown, the second sampling resistor module as follows Figure 5 The resistor R2 is shown. The resistance values ​​of resistors R1 and R2 are the same as those of resistor R0.

[0035] Step S110, obtaining the current detection value of the first bridge arm, includes: obtaining the voltage value obtained by the first sampling resistor module to characterize the current detection result of the first bridge arm, as the current detection value of the first bridge arm.

[0036] Step S110, obtaining the current detection value of the second bridge arm, includes: obtaining the voltage value obtained by the second sampling resistor module to characterize the current detection result of the second bridge arm, as the current detection value of the second bridge arm.

[0037] Figure 5 This is a schematic diagram of a fault detection circuit for an H-bridge circuit in a switching power amplifier. When the magnetic bearing control system is in normal operation, a fault in any power switching device in the switching power amplifier will cause the magnetic bearing to malfunction. This invention proposes a power amplifier fault detection circuit, such as... Figure 5As shown, a power resistor, such as resistor R1 and resistor R2, is added to each of the left and right arms of the H-bridge for current sensing. The detection voltage signals for the current in each arm of the left and right bridge are V, respectively. F1 V F2 .like Figure 5 As shown, in Figure 4 Based on the circuit shown, resistor R1 is connected between the anode of diode D2 and ground, and resistor R2 is connected between the source of switching transistor S2 and ground. The current detection signal of the left arm of the H-bridge (i.e., the arm where switching transistor S1 is located) is detected from the common terminal of the anode of diode D2 and resistor R1. This current detection signal V is used to characterize the current detection value of the arm where switching transistor S1 is located. F1 The current detection signal of the right arm of the H-bridge (i.e., the arm where switch S2 is located) is obtained by detecting the current from the source of switch S2 and the common terminal of resistor R2. This current detection signal V is used to characterize the current detection value of the arm where switch S2 is located. F2 .

[0038] The solution of this invention can quickly and accurately locate the fault point and fault type of the switching power amplifier by analyzing the current sampling signal values ​​of each bridge arm in the switching power amplifier, which greatly improves the efficiency of fault diagnosis and reduces the time cost of fault repair.

[0039] In some implementations, the specific process of determining whether the switching power amplifier has malfunctioned based on the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller in step S120 is described in the following exemplary description.

[0040] The following is combined Figure 2 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention for determining whether the switching power amplifier has failed. The specific process of determining whether the switching power amplifier has failed in step S120 is further explained, including steps S210 to S260.

[0041] Step S210: Based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm, determine the sum of the current detection values ​​of the first bridge arm, and record it as the total current detection value of the first bridge arm; wherein, the total current detection value of the first bridge arm is represented by voltage V1.

[0042] Step S220: Based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm, determine the sum of the current detection values ​​of the second bridge arm, and record it as the total current detection value of the second bridge arm; wherein, the total current detection value of the second bridge arm is represented by voltage V2.

[0043] Step S230: Determine the current threshold of the switching power amplifier based on the switching cycle of the switching power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller.

[0044] Step S240: Determine whether the following conditions are met: the total current detection value of the first bridge arm is 0 or the total current detection value of the first bridge arm is the current threshold of the switching power amplifier; and the total current detection value of the second bridge arm is 0 or the total current detection value of the second bridge arm is the current threshold of the switching power amplifier; wherein, the current threshold of the switching power amplifier is as follows: Tk*fc*i*R 0 The calculated current value has a preset current threshold greater than 0.

[0045] Step S250: If the condition is satisfied, then the switching power amplifier is determined to be faulty, and an alert message is outputting the fault location and / or fault type of the switching power amplifier.

[0046] Step S260: If it is determined that the condition is not met, then it is determined that the switching power amplifier is not faulty. The switching power amplifier continues to operate, and then returns to the previous state to obtain the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller in the next switching cycle of the switching power amplifier at the set sampling frequency. Then, based on the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, it is determined whether the switching power amplifier is faulty, and the fault detection of the switching power amplifier continues. In other words, if it is determined that the switching power amplifier is not faulty, after a set interval, the current detection value of the first bridge arm is obtained again at a set sampling frequency during the next switching cycle of the switching power amplifier, the current detection value of the second bridge arm is obtained, and the coil current of the magnetic bearing controlled by the magnetic bearing controller is obtained; then, based on the current detection values ​​of the first bridge arm, the current detection values ​​of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, it is determined whether the switching power amplifier is faulty, and the fault detection of the switching power amplifier continues.

[0047] Figure 6 This is a schematic diagram of the current waveform of a three-level switching power amplifier. When the switching power amplifier uses three-level modulation, the timing sequence of the drive signals for the switching power devices in the amplifier during the charging of the magnetic bearing coil is as follows: Figure 6 As shown. By Figure 6It can be seen that the switching power amplifier sequentially enters three states within one switching cycle Tk: charging, upward freewheeling, and downward freewheeling. Specifically, in Figure 6 In the example shown, the duty cycle U of the switch S1 gs1 When the voltage level is high, switch S1 is turned on, and the duty cycle U of switch S1 is... gs1 When the voltage level is low, switch S1 is turned off; the duty cycle U of switch S2 is low. gs2 When the voltage level is high, switch S2 is turned on, and the duty cycle U of switch S2 is... gs2 When the voltage level is low, the switching transistor S2 is turned off; the output current i of the switching power amplifier is the current i of the magnetic bearing coil.

[0048] Among them, during the time interval 0~t1, the duty cycle U of the switching transistor S1 gs1 When the voltage level is high, the duty cycle U of the switch S2 is... gs2 When the signal is high, the switching power amplifier is in a charging state, and the output current i of the switching power amplifier starts from the minimum current i. min Rise to i max During the time interval t1 to 0.5T, the duty cycle U of the switching transistor S1 gs1 When the voltage level is low, the duty cycle U of the switch S2 is... gs2 When the signal is high, the switching power amplifier is in a downward freewheeling state, and the output current i of the switching power amplifier is determined by the maximum current i. max Drop to minimum current i min During the time interval 0.5T to (0.5T+t1), the duty cycle U of the switching transistor S1 gs1 When the voltage level is high, the duty cycle U of the switch S2 is... gs2 When the signal is high, the switching power amplifier is in a charging state, and the output current i of the switching power amplifier is reduced from the minimum current i. min Rise to i max During the time interval (0.5T+t1)~T, the duty cycle U of the switching transistor S1 gs1 When the voltage level is high, the duty cycle U of the switch S2 is... gs2 When the voltage level is low, the switching power amplifier is in upward freewheeling mode, and the output current i of the switching power amplifier is determined by the maximum current i. max Drop to minimum current i min The subsequent switching power amplifier will operate periodically according to the three states described above (charging, downward freewheeling, and upward freewheeling).

[0049] See Figure 6 In the example shown, the driving timing of the magnetic bearing coil during discharge is similar to that during charging, except for the different duty cycle. The state analysis will not be elaborated here. During discharge, the switching power amplifier will have three states: upward freewheeling, discharging, and downward freewheeling.

[0050] See Figure 4 , Figure 5 and Figure 6 The example shown illustrates the fault analysis of switching power devices in a switching power amplifier. as follows : When the switching power amplifier is operating normally, the magnetic bearing coil exists in either charging, upward freewheeling, or downward freewheeling states, or discharging, upward freewheeling, or downward freewheeling states. During one switching cycle, the voltage signal V, used to characterize the current detection value of the bridge arm containing the switching transistor S1, is... F1 The voltage signal V used to characterize the current detection value of the bridge arm where the switching transistor S2 is located. F2 There is no such thing as always being 0 or always being 0. iR 0 In this case, i represents the output current of the switching power amplifier. There are two types of faults in the switching power devices of a switching power amplifier: short circuit and open circuit, as detailed below: 1) Switch S1 is short-circuited, while switch S2 is normal.

[0051] At this time, the current in the magnetic bearing coil only exists in two states: charging and upward freewheeling; there is no downward freewheeling state. Therefore, it is possible to detect V within one switching cycle. F1 The voltage value remains at 0; V F2 The voltage value during charging is iR 0 , is 0 when in the upward continuous flow state.

[0052] 2) Switch S1 is normal, switch S2 is short-circuited.

[0053] At this time, the current i in the magnetic bearing coil only exists in two states: charging and downward freewheeling; there is no upward freewheeling state. Therefore, it is possible to detect V within one switching cycle. F1 The voltage is 0 during charging and V during freewheeling. F1 Voltage value iR 0 V F2 The voltage value has always been iR 0 .

[0054] 3) Switch S1 is open-circuited, while switch S2 is normal.

[0055] At this time, the current i in the magnetic bearing coil only exists in two states: discharge and downward freewheeling; there is no upward freewheeling state. Therefore, it is possible to detect V within one switching cycle. F1 The voltage value has always been iR 0 V F2 The voltage value during discharge is 0 V F2 The voltage value in the downward freewheeling state is iR 0 .

[0056] 4) Switch S1 is normal, switch S2 is open circuit.

[0057] At this time, the current i in the magnetic bearing coil only exists in two states: discharge and upward freewheeling; there is no downward freewheeling state. Therefore, it is possible to detect V within one switching cycle. F1 The voltage value during discharge is iR 0 V F1 The voltage value during upward freewheeling is 0 V F2 The voltage value has always been 0 .

[0058] The following is an exemplary description of the specific judgment logic for fault detection of switching power devices in a switching power amplifier. Figure 7 This is a schematic diagram of the control system for a switching power amplifier. Figure 7 As shown, the control system of the switching power amplifier includes: a controller MCU, an isolation circuit, a power amplifier bridge, a magnetic bearing coil, a current sensor, and current sampling resistors (such as resistors R1 and R2). The controller MCU outputs a PWM signal to the isolation circuit, which then outputs an isolated PWM signal to the power amplifier bridge. The power amplifier bridge outputs a current i to the magnetic bearing coil. The current i is sampled by the current sensor to obtain a voltage u, and the current i is sampled by the current sampling resistors to obtain a voltage signal V. F1 and V F2 .

[0059] Among them, isolation circuits such as opto-isolation circuits, and power amplifier bridge circuits such as... Figure 5 The power amplifier bridge circuit includes fault detection. A current sensor, such as a Hall effect current sensor, is used. The input of the Hall effect current sensor is connected in series with the magnetic bearing coil to detect the current signal of the magnetic bearing coil, obtaining a detection signal of current i. The output of the Hall effect current sensor is a voltage signal characterizing the current signal of the magnetic bearing coil. The current sampling resistors are resistors R1 and R2.

[0060] In this invention, sampling resistors are added to each bridge arm to detect the current signal of each bridge arm, and the sum of the current sampling signal values ​​of each bridge arm within the switching cycle is calculated. By comparing the sum of the current sampling signal values ​​of each bridge arm with the fault type truth table, the fault location and fault type of the switching power amplifier can be obtained, which greatly improves the efficiency of fault diagnosis and reduces the time cost of fault repair.

[0061] In some implementations, step S210, determining the sum of the current detection values ​​of the first bridge arm based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm, and recording it as the total current detection value of the first bridge arm, includes: taking the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm as the sum of the current detection values ​​of the first bridge arm, and recording it as the total current detection value of the first bridge arm.

[0062] And / or, in step S220, the sum of the current detection values ​​of the second bridge arm is determined based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm, and recorded as the total current detection value of the second bridge arm. This includes: taking the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm as the sum of the current detection values ​​of the second bridge arm, and recording it as the total current detection value of the second bridge arm.

[0063] And / or, in step S230, determining the current threshold of the switching power amplifier based on the switching period of the switching power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller includes: using the product of the switching period of the switching power amplifier, the set sampling frequency, the coil current of the magnetic bearing controlled by the magnetic bearing controller, and the coil resistance of the magnetic bearing controlled by the magnetic bearing controller as the current threshold of the switching power amplifier.

[0064] Figure 8 This is a flowchart illustrating the fault detection method for the switching power amplifier in a magnetic bearing controller. The control system block diagram of the switching power amplifier is shown below. Figure 7 As shown in the figure, the specific flowchart for fault detection of switching power devices in a switching power amplifier is as follows: Figure 8 As shown. Figure 8 As shown, the fault detection method for the switching power amplifier in the magnetic bearing controller includes: Step 1: Set the sampling frequency of the current detection signal of the controller MCU. fc Then proceed to step 2. Data sampling is performed by the main control chip, and the sampling frequency is set by software programming; the sampling frequency is how many data points the main control chip samples per second.

[0065] Step 2: The controller MCU uses a sampling frequency. fc Acquire current detection signals, such as the voltage signal V used to characterize the current detection value of the bridge arm where the switching transistor S1 is located. F1 and the voltage signal V used to characterize the current detection value of the bridge arm where the switching transistor S2 is located. F2Save the sampled data and then proceed to step 3.

[0066] Step 3: The controller MCU is programmed to calculate the sum of the current detection signal sampling values ​​within the switching cycle Tk, where V1 = Tk * fc *V F1 V2=Tk* fc *V F2 Save the calculated data, and then proceed to step 4. V1 is the voltage signal V sampled at sampling frequency fc within the switching period Tk. F1 The sum of V2 and V2 is the voltage signal V sampled at sampling frequency fc during the switching period Tk. F2 The sum of the values. The switching frequency fc of a magnetic bearing switching power amplifier is generally between 10kHz and 100kHz, which can be converted into a switching period.

[0067] By adopting the solution of the present invention, it is only necessary to add sampling resistors to the original bridge arms of each bridge arm in the switching power amplifier, so as to realize the online determination of the fault point and fault type of the switching power amplifier at low cost, which greatly improves the efficiency of fault diagnosis and reduces the time cost of fault repair.

[0068] In some implementations, step S250 determines that the switching power amplifier has failed and outputs an alert message indicating the location and / or type of the fault, including at least one of the following fault determination scenarios: The first fault determination scenario: If the total current detection value of the first bridge arm is determined to be 0, then the first switching transistor is determined to have a short circuit fault, and an alert message is output indicating that the fault location of the switching power amplifier is the location of the first switching transistor and / or the fault type of the switching power amplifier is a short circuit fault; the sum of the current detection values ​​of the first bridge arm is the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm.

[0069] The second fault determination scenario: If the total current detected value of the first bridge arm is determined to be equal to the current threshold of the switching power amplifier, then the first switching transistor is determined to have an open-circuit fault, and an alert message is output indicating that the fault location of the switching power amplifier is the location of the first switching transistor and / or the fault type of the switching power amplifier is an open-circuit fault; the current threshold of the switching power amplifier is the product of the switching period of the switching power amplifier, the set sampling frequency, the coil current of the magnetic bearing controlled by the magnetic bearing controller, and the coil resistance of the magnetic bearing controlled by the magnetic bearing controller.

[0070] The third fault determination scenario: If the total current detection value of the second bridge arm is determined to be 0, then the second switching transistor is determined to have an open circuit fault, and an alert message is output indicating that the fault location of the switching power amplifier is the location of the second switching transistor and / or the fault type of the switching power amplifier is an open circuit fault; the sum of the current detection values ​​of the second bridge arm is the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm.

[0071] The fourth fault determination scenario: If the total current detected value of the second bridge arm is determined to be equal to the current threshold of the switching power amplifier, then a short circuit fault is determined to have occurred in the second switching transistor, and an alert message is output indicating that the fault location of the switching power amplifier is the location of the second switching transistor and / or that the fault type of the switching power amplifier is a short circuit fault; the current threshold of the switching power amplifier is the product of the switching period of the switching power amplifier, the set sampling frequency, the coil current of the magnetic bearing controlled by the magnetic bearing controller, and the coil resistance of the magnetic bearing controlled by the magnetic bearing controller.

[0072] like Figure 8 As shown, the fault detection method for the switching power amplifier in the magnetic bearing controller also includes: Step 4: The sums V1 and V2 calculated from the current detection signal sample values ​​are judged according to the truth table, as shown in Table 1. If a fault occurs, the fault location and fault type are output; if no fault occurs, the controller MCU will clear the data of the previous switching cycle, specifically clearing the sums V1 and V2 calculated from the current detection signal sample values ​​in Step 3, and re-sample and calculate in the new switching cycle. The solution of this invention compares the sampled values ​​of the switching power device with the truth table in each switching cycle. Therefore, the detection in the next switching cycle needs to clear the sampled data of the previous switching cycle to ensure that the compared data are all within one switching cycle.

[0073]

[0074] In Table 1, ' / ' indicates no judgment is performed; that is, it is only necessary to judge whether V1 is 0 or not. Tk*fc*i*R 0 And determine whether V2 is 0 or not. Tk*fc*i*R 0 .

[0075] In the solution of this invention, the current detection signal on each bridge arm is sampled by the controller MCU, and the sum of the sampled signals of each bridge arm within the switching cycle is calculated. By analyzing the sum of the current sampled signal values ​​of each bridge arm and the fault type truth table, the fault location and fault type of the power amplifier switching power device are determined. This enables online determination of the fault point and fault type of the switching power amplifier, greatly improving the efficiency of fault diagnosis and reducing the time cost of fault repair.

[0076] The solution of this invention is applicable to magnetic bearing switching power amplifiers, as well as analog and digital power amplifiers; that is, the driving signal of the magnetic bearing switching power amplifier can be an analog signal or a digital signal.

[0077] The technical solution of this embodiment uses a switching power amplifier for a magnetic bearing controller. The switching power amplifier has an H-bridge, with a first arm (e.g., the left arm) and a second arm (e.g., the right arm). The first arm has a first switching transistor (e.g., switching transistor S1), and the second arm has a second switching transistor (e.g., switching transistor S2). When fault detection of the switching power amplifier is required, within a set switching period (e.g., switching period Tk) of the H-bridge, the current detection value (e.g., voltage signal V) of the first arm of the H-bridge is acquired at a set sampling frequency (e.g., sampling frequency fc). F1 ), and the current detection value of the second bridge arm (such as voltage signal V). F2 Based on the current detection values ​​of the first and second bridge arms, the set sampling frequency, and the set switching period, the system determines whether a fault has occurred in the switching power amplifier, such as whether a short circuit or open circuit fault has occurred in the first and second switching transistors, thus achieving fault detection of the switching power amplifier. Therefore, by determining whether a fault has occurred in the switching power amplifier based on the current detection values ​​of the first and second bridge arms, the set sampling frequency, and the set switching period, online fault detection of the switching power amplifier can be achieved, such as online determination of the fault point and fault type, improving fault diagnosis efficiency.

[0078] According to embodiments of the present invention, a fault detection device for a switching power amplifier, corresponding to a fault detection method for a switching power amplifier, is also provided. See also Figure 3 The diagram shows a structural schematic of an embodiment of the device of the present invention. This fault detection device for a switching power amplifier can be applied to a magnetic bearing controller; the switching power amplifier includes an H-bridge, the H-bridge having a first bridge arm and a second bridge arm, the first bridge arm having a first switching transistor, and the second bridge arm having a second switching transistor, the first switching transistor being as follows... Figure 4 The switch S1 shown, the second switch as... Figure 5The switch S2 shown is provided in this invention; the present invention proposes a fault detection circuit for a power amplifier switching power device. Figure 4 This is a schematic diagram of the H-bridge circuit of a switching power amplifier. (Example:) Figure 4 The switching power amplifier shown includes: switching transistors S1 and S2, diodes D1 and D2, resistor R0, and inductor L. Resistor R0 represents the resistive portion of the bearing coil, and inductor L represents the inductive portion of the magnetic bearing coil. Switches S1 and S2 are both power switching devices, such as MOSFETs and IGBTs. When both switching transistors S1 and S2 are MOSFETs, the DC power supply V... CC The source of the switching transistor S1 is connected to the drain of the switching transistor S1 and the cathode of the diode D1, respectively. The source of the switching transistor S1 is connected to the anode of the diode D1 via resistor R0 and inductor L. The switching transistor S1 is also connected to the cathode of the diode D2, and the anode of the diode D2 is grounded. The anode of the diode D1 is also connected to the drain of the switching transistor S2, and the source of the switching transistor S2 is grounded.

[0079] The magnetic bearing switching power amplifier (i.e., the switching power amplifier in the magnetic bearing controller) adopts the following... Figure 4 The diagram shows a half-bridge power topology using three-level modulation. With three-level modulation, the switching power amplifier will have three states: charging, freewheeling, and discharging. The freewheeling state is further subdivided into upward freewheeling and downward freewheeling: 1) Switches S1 and S2 are simultaneously turned on, and the bearing coil is in a charging state; 2) Switches S1 and S2 are simultaneously turned off, and the bearing coil is in a discharging state; 3) Switch S1 is turned on and switch S2 is turned off, and the bearing coil is in an upward freewheeling state; 4) Switch S1 is turned off and switch S2 is turned on, and the bearing coil is in a downward freewheeling state. In the solution of this invention, as... Figure 3 As shown, the fault detection device for the switching power amplifier includes: an acquisition unit 102 and a control unit 104.

[0080] The acquisition unit 102 is configured to, during the operation of the switching power amplifier, when fault detection of the switching power amplifier is required, acquire the current detection value of the first bridge arm, acquire the current detection value of the second bridge arm, and acquire the coil current of the magnetic bearing controlled by the magnetic bearing controller within the current switching cycle of the switching power amplifier, at a set sampling frequency; wherein, the current detection value of the first bridge arm is as follows: Figure 5 The voltage signal V shown F1 The current detection signal of the second bridge arm is as follows: Figure 5 The voltage signal V shown F2The magnetic bearing controller controls the coil current of the magnetic bearing, such as the magnetic bearing coil current i. For the specific functions and processing of the acquisition unit 102, please refer to step S110.

[0081] The control unit 104 is configured to determine whether the switching power amplifier has malfunctioned based on the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, thereby achieving fault detection of the switching power amplifier. The specific functions and processing of this control unit 104 are described in step S120.

[0082] The present invention proposes a fault detection scheme for a magnetic bearing switching power amplifier. By using the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, the scheme determines whether the switching power amplifier has a fault, and judges the fault location and fault type of the switching power device of the power amplifier. This scheme enables online determination of the fault point and fault type of the switching power amplifier, greatly improving the efficiency of fault diagnosis and reducing the time cost of fault repair.

[0083] In some embodiments, a first sampling resistor module is provided between the grounding terminal of the first bridge arm and ground; a second sampling resistor module is provided between the grounding terminal of the second bridge arm and ground; and the resistance values ​​of both the first and second sampling resistor modules are the same as the resistance value of the coil of the magnetic bearing; wherein, the first sampling resistor module is as follows: Figure 5 The resistor R1 shown, the second sampling resistor module as follows Figure 5 The resistor R2 is shown. The resistance values ​​of resistors R1 and R2 are the same as those of resistor R0.

[0084] The acquisition unit 102 acquires the current detection value of the first bridge arm, including: the acquisition unit 102 is further configured to acquire the voltage value obtained by the first sampling resistor module to characterize the current detection result of the first bridge arm, as the current detection value of the first bridge arm.

[0085] The acquisition unit 102 acquires the current detection value of the second bridge arm, including: the acquisition unit 102 is further configured to acquire the voltage value obtained by the second sampling resistor module to characterize the current detection result of the second bridge arm, as the current detection value of the second bridge arm.

[0086] Figure 5This is a schematic diagram of a fault detection circuit for an H-bridge circuit in a switching power amplifier. When the magnetic bearing control system is in normal operation, a fault in any power switching device in the switching power amplifier will cause the magnetic bearing to malfunction. This invention proposes a power amplifier fault detection circuit, such as... Figure 5 As shown, a power resistor, such as resistor R1 and resistor R2, is added to each of the left and right arms of the H-bridge for current sensing. The detection voltage signals for the current in each arm of the left and right bridge are V, respectively. F1 V F2 .like Figure 5 As shown, in Figure 4 Based on the circuit shown, resistor R1 is connected between the anode of diode D2 and ground, and resistor R2 is connected between the source of switching transistor S2 and ground. The current detection signal of the left arm of the H-bridge (i.e., the arm where switching transistor S1 is located) is detected from the common terminal of the anode of diode D2 and resistor R1. This current detection signal V is used to characterize the current detection value of the arm where switching transistor S1 is located. F1 The current detection signal of the right arm of the H-bridge (i.e., the arm where switch S2 is located) is obtained by detecting the current from the source of switch S2 and the common terminal of resistor R2. This current detection signal V is used to characterize the current detection value of the arm where switch S2 is located. F2 .

[0087] The solution of this invention can quickly and accurately locate the fault point and fault type of the switching power amplifier by analyzing the current sampling signal values ​​of each bridge arm in the switching power amplifier, which greatly improves the efficiency of fault diagnosis and reduces the time cost of fault repair.

[0088] In some embodiments, the control unit 104 determines whether the switching power amplifier has malfunctioned based on the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, including: The control unit 104 is further configured to determine the sum of the current detection values ​​of the first bridge arm based on the switching cycle of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm, and denoted as the total current detection value of the first bridge arm; wherein the total current detection value of the first bridge arm is represented by voltage V1. The specific functions and processing of the control unit 104 are further described in step S210.

[0089] The control unit 104 is further configured to determine the sum of the current detection values ​​of the second bridge arm based on the switching cycle of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm, and denoted as the total current detection value of the second bridge arm; wherein the total current detection value of the second bridge arm is represented by voltage V2. The specific functions and processing of the control unit 104 are further described in step S220.

[0090] The control unit 104 is further configured to determine the current threshold of the switching power amplifier based on the switching cycle of the switching power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller. The specific functions and processing of this control unit 104 are further described in step S230.

[0091] The control unit 104 is further configured to determine whether the following conditions are met: the total current detection value of the first bridge arm is 0 or the total current detection value of the first bridge arm is the current threshold of the switching power amplifier; and the total current detection value of the second bridge arm is 0 or the total current detection value of the second bridge arm is the current threshold of the switching power amplifier; wherein, the current threshold of the switching power amplifier is as follows: Tk*fc*i*R 0 The calculated current value has a preset current threshold greater than 0. For the specific functions and processing of this control unit 104, please refer to step S240.

[0092] The control unit 104 is further configured to, if the condition is met, determine that the switching power amplifier has malfunctioned, and output a reminder message indicating the fault location and / or fault type of the switching power amplifier. The specific functions and processing of this control unit 104 are further described in step S250.

[0093] The control unit 104 is further configured to, if the condition is not met, determine that the switching power amplifier is not faulty, continue to control the switching power amplifier to operate, and then return to the previous state. The acquisition unit 102 is further configured to, in the next switching cycle of the switching power amplifier, acquire the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller at a set sampling frequency; then, based on the current detection values ​​of the first bridge arm, the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, determine again whether the switching power amplifier is faulty, and continue to perform fault detection on the switching power amplifier. The specific functions and processing of the control unit 104 are also described in step S260. In other words, the acquisition unit 102 is specifically configured to, after determining that the switching power amplifier has not malfunctioned, acquire the current detection value of the first bridge arm, acquire the current detection value of the second bridge arm, and acquire the coil current of the magnetic bearing controlled by the magnetic bearing controller in the next switching cycle of the switching power amplifier at a set sampling frequency after a set interval time; furthermore, the control unit 104 is specifically configured to, based on the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, determine whether the switching power amplifier has malfunctioned, and continue to perform fault detection on the switching power amplifier.

[0094] Figure 6 This is a schematic diagram of the current waveform of a three-level switching power amplifier. When the switching power amplifier uses three-level modulation, the timing sequence of the drive signals for the switching power devices in the amplifier during the charging of the magnetic bearing coil is as follows: Figure 6 As shown. By Figure 6 It can be seen that the switching power amplifier sequentially enters three states within one switching cycle Tk: charging, upward freewheeling, and downward freewheeling. Specifically, in Figure 6 In the example shown, the duty cycle U of the switch S1 gs1 When the voltage level is high, switch S1 is turned on, and the duty cycle U of switch S1 is... gs1 When the voltage level is low, switch S1 is turned off; the duty cycle U of switch S2 is low. gs2 When the voltage level is high, switch S2 is turned on, and the duty cycle U of switch S2 is... gs2 When the voltage level is low, the switching transistor S2 is turned off; the output current i of the switching power amplifier is the current i of the magnetic bearing coil.

[0095] Among them, during the time interval 0~t1, the duty cycle U of the switching transistor S1 gs1 When the voltage level is high, the duty cycle U of the switch S2 is... gs2When the signal is high, the switching power amplifier is in a charging state, and the output current i of the switching power amplifier starts from the minimum current i. min Rise to i max During the time interval t1 to 0.5T, the duty cycle U of the switching transistor S1 gs1 When the voltage level is low, the duty cycle U of the switch S2 is... gs2 When the signal is high, the switching power amplifier is in a downward freewheeling state, and the output current i of the switching power amplifier is determined by the maximum current i. max Drop to minimum current i min During the time interval 0.5T to (0.5T+t1), the duty cycle U of the switching transistor S1 gs1 When the voltage level is high, the duty cycle U of the switch S2 is... gs2 When the signal is high, the switching power amplifier is in a charging state, and the output current i of the switching power amplifier is reduced from the minimum current i. min Rise to i max During the time interval (0.5T+t1)~T, the duty cycle U of the switching transistor S1 gs1 When the voltage level is high, the duty cycle U of the switch S2 is... gs2 When the voltage level is low, the switching power amplifier is in upward freewheeling mode, and the output current i of the switching power amplifier is determined by the maximum current i. max Drop to minimum current i min The subsequent switching power amplifier will operate periodically according to the three states described above (charging, downward freewheeling, and upward freewheeling).

[0096] See Figure 6 In the example shown, the driving timing of the magnetic bearing coil during discharge is similar to that during charging, except for the different duty cycle. The state analysis will not be elaborated here. During discharge, the switching power amplifier will have three states: upward freewheeling, discharging, and downward freewheeling.

[0097] See Figure 4 , Figure 5 and Figure 6 The example shown illustrates the fault analysis of switching power devices in a switching power amplifier. as follows : When the switching power amplifier is operating normally, the magnetic bearing coil exists in either charging, upward freewheeling, or downward freewheeling states, or discharging, upward freewheeling, or downward freewheeling states. During one switching cycle, the voltage signal V, used to characterize the current detection value of the bridge arm containing the switching transistor S1, is... F1 The voltage signal V used to characterize the current detection value of the bridge arm where the switching transistor S2 is located. F2 There is no such thing as always being 0 or always being 0. iR 0 In this case, i represents the output current of the switching power amplifier. There are two types of faults in the switching power devices of a switching power amplifier: short circuit and open circuit, as detailed below: 1) Switch S1 is short-circuited, while switch S2 is normal.

[0098] At this time, the current in the magnetic bearing coil only exists in two states: charging and upward freewheeling; there is no downward freewheeling state. Therefore, it is possible to detect V within one switching cycle. F1 The voltage value remains at 0; V F2 The voltage value during charging is iR 0 , is 0 when in the upward continuous flow state.

[0099] 2) Switch S1 is normal, switch S2 is short-circuited.

[0100] At this time, the current i in the magnetic bearing coil only exists in two states: charging and downward freewheeling; there is no upward freewheeling state. Therefore, it is possible to detect V within one switching cycle. F1 The voltage is 0 during charging and V during freewheeling. F1 Voltage value iR 0 V F2 The voltage value has always been iR 0 .

[0101] 3) Switch S1 is open-circuited, while switch S2 is normal.

[0102] At this time, the current i in the magnetic bearing coil only exists in two states: discharge and downward freewheeling; there is no upward freewheeling state. Therefore, it is possible to detect V within one switching cycle. F1 The voltage value has always been iR 0 V F2 The voltage value during discharge is 0 V F2 The voltage value in the downward freewheeling state is iR 0 .

[0103] 4) Switch S1 is normal, switch S2 is open circuit.

[0104] At this time, the current i in the magnetic bearing coil only exists in two states: discharge and upward freewheeling; there is no downward freewheeling state. Therefore, it is possible to detect V within one switching cycle. F1 The voltage value during discharge is iR 0 V F1 The voltage value during upward freewheeling is 0 V F2 The voltage value has always been 0 .

[0105] The following is an exemplary description of the specific judgment logic for fault detection of switching power devices in a switching power amplifier. Figure 7 This is a schematic diagram of the control system for a switching power amplifier. Figure 7As shown, the control system of the switching power amplifier includes: a controller MCU, an isolation circuit, a power amplifier bridge, a magnetic bearing coil, a current sensor, and current sampling resistors (such as resistors R1 and R2). The controller MCU outputs a PWM signal to the isolation circuit, which then outputs an isolated PWM signal to the power amplifier bridge. The power amplifier bridge outputs a current i to the magnetic bearing coil. The current i is sampled by the current sensor to obtain a voltage u, and the current i is sampled by the current sampling resistors to obtain a voltage signal V. F1 and V F2 .

[0106] Among them, isolation circuits such as opto-isolation circuits, and power amplifier bridge circuits such as... Figure 5 The power amplifier bridge circuit includes fault detection. A current sensor, such as a Hall effect current sensor, is used. The input of the Hall effect current sensor is connected in series with the magnetic bearing coil to detect the current signal of the magnetic bearing coil, obtaining a detection signal of current i. The output of the Hall effect current sensor is a voltage signal characterizing the current signal of the magnetic bearing coil. The current sampling resistors are resistors R1 and R2.

[0107] In this invention, sampling resistors are added to each bridge arm to detect the current signal of each bridge arm, and the sum of the current sampling signal values ​​of each bridge arm within the switching cycle is calculated. By comparing the sum of the current sampling signal values ​​of each bridge arm with the fault type truth table, the fault location and fault type of the switching power amplifier can be obtained, which greatly improves the efficiency of fault diagnosis and reduces the time cost of fault repair.

[0108] In some embodiments, the control unit 104 determines the sum of the current detection values ​​of the first bridge arm based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm, and records it as the total current detection value of the first bridge arm. Specifically, the control unit 104 is further configured to use the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm as the sum of the current detection values ​​of the first bridge arm, and record it as the total current detection value of the first bridge arm.

[0109] And / or, the control unit 104 determines the sum of the current detection values ​​of the second bridge arm based on the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm, and records it as the total current detection value of the second bridge arm. Specifically, the control unit 104 is further configured to use the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm as the sum of the current detection values ​​of the second bridge arm, and record it as the total current detection value of the second bridge arm.

[0110] And / or, the control unit 104 determines the current threshold of the switching power amplifier based on the switching period of the switching power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, including: the control unit 104 is further configured to use the product of the switching period of the switching power amplifier, the set sampling frequency, the coil current of the magnetic bearing controlled by the magnetic bearing controller, and the coil resistance of the magnetic bearing controlled by the magnetic bearing controller as the current threshold of the switching power amplifier.

[0111] Figure 8 This is a flowchart illustrating the fault detection method for the switching power amplifier in a magnetic bearing controller. The control system block diagram of the switching power amplifier is shown below. Figure 7 As shown in the figure, the specific flowchart for fault detection of switching power devices in a switching power amplifier is as follows: Figure 8 As shown. Figure 8 As shown, the fault detection method for the switching power amplifier in the magnetic bearing controller includes: Step 1: Set the sampling frequency of the current detection signal of the controller MCU. fc Then proceed to step 2.

[0112] Step 2: The controller MCU uses a sampling frequency. fc Acquire current detection signals, such as the voltage signal V used to characterize the current detection value of the bridge arm where the switching transistor S1 is located. F1 and the voltage signal V used to characterize the current detection value of the bridge arm where the switching transistor S2 is located. F2 Save the sampled data and then proceed to step 3.

[0113] Step 3: The controller MCU is programmed to calculate the sum of the current detection signal sampling values ​​within the switching cycle Tk, where V1 = Tk * fc *V F1 V2=Tk* fc *V F2 Save the calculated data, and then proceed to step 4. V1 is the voltage signal V sampled at sampling frequency fc within the switching period Tk. F1 The sum of V2 and V2 is the voltage signal V sampled at sampling frequency fc during the switching period Tk. F2 The sum of .

[0114] By adopting the solution of the present invention, it is only necessary to add sampling resistors to the original bridge arms of each bridge arm in the switching power amplifier, so as to realize the online determination of the fault point and fault type of the switching power amplifier at low cost, which greatly improves the efficiency of fault diagnosis and reduces the time cost of fault repair.

[0115] In some embodiments, the control unit 104 determines that the switching power amplifier has malfunctioned and outputs an alert message indicating the location and / or type of the fault in the switching power amplifier, including at least one of the following fault determination scenarios: The first fault determination scenario: The control unit 104 is further configured to determine that the first switching transistor has a short circuit fault if the total current detection value of the first bridge arm is determined to be equal to 0, and to output a reminder message indicating that the fault location of the switching power amplifier is the location of the first switching transistor and / or the fault type of the switching power amplifier is a short circuit fault; the sum of the current detection values ​​of the first bridge arm is the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm.

[0116] The second fault determination scenario: The control unit 104 is further configured to determine that the first switching transistor has an open-circuit fault if the total current detection value of the first bridge arm is equal to the current threshold of the switching power amplifier, and output a reminder message indicating that the fault location of the switching power amplifier is the location of the first switching transistor and / or the fault type of the switching power amplifier is an open-circuit fault; the current threshold of the switching power amplifier is the product of the switching period of the switching power amplifier, the set sampling frequency, the coil current of the magnetic bearing controlled by the magnetic bearing controller, and the coil resistance of the magnetic bearing controlled by the magnetic bearing controller.

[0117] The third fault determination scenario: The control unit 104 is further configured to determine that the second switch has an open circuit fault if the total current detection value of the second bridge arm is determined to be equal to 0, and output a reminder message that the fault location of the switching power amplifier is the location of the second switch and / or the fault type of the switching power amplifier is an open circuit fault; the sum of the current detection values ​​of the second bridge arm is the product of the switching period of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm.

[0118] The fourth fault determination scenario: The control unit 104 is further configured to determine that the second switching transistor has a short circuit fault if the total current detection value of the second bridge arm is equal to the current threshold of the switching power amplifier, and output a reminder message indicating that the fault location of the switching power amplifier is the location of the second switching transistor and / or the fault type of the switching power amplifier is a short circuit fault; the current threshold of the switching power amplifier is the product of the switching period of the switching power amplifier, the set sampling frequency, the coil current of the magnetic bearing controlled by the magnetic bearing controller, and the coil resistance of the magnetic bearing controlled by the magnetic bearing controller.

[0119] like Figure 8 As shown, the fault detection method for the switching power amplifier in the magnetic bearing controller also includes: Step 4: The sums V1 and V2 calculated from the current detection signal sample values ​​are judged according to the truth table, as shown in Table 1. If a fault occurs, the fault location and fault type are output; if no fault occurs, the controller MCU will clear the data of the previous switching cycle, specifically clearing the sums V1 and V2 calculated from the current detection signal sample values ​​in Step 3, and re-sample and calculate in the new switching cycle. The solution of this invention compares the sampled values ​​of the switching power device with the truth table in each switching cycle. Therefore, the detection in the next switching cycle needs to clear the sampled data of the previous switching cycle to ensure that the compared data are all within one switching cycle.

[0120] In Table 1, ' / ' indicates no judgment is performed; that is, it is only necessary to judge whether V1 is 0 or not. Tk*fc*i*R 0 And determine whether V2 is 0 or not. Tk*fc*i*R 0 .

[0121] In the solution of this invention, the current detection signal on each bridge arm is sampled by the controller MCU, and the sum of the sampled signals of each bridge arm within the switching cycle is calculated. By analyzing the sum of the current sampled signal values ​​of each bridge arm and the fault type truth table, the fault location and fault type of the power amplifier switching power device are determined. This enables online determination of the fault point and fault type of the switching power amplifier, greatly improving the efficiency of fault diagnosis and reducing the time cost of fault repair.

[0122] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0123] According to an embodiment of the present invention, a magnetic bearing controller corresponding to a fault detection device for a switching power amplifier is also provided. This magnetic bearing controller may include the fault detection device for the switching power amplifier described above.

[0124] Since the processing and functions implemented by the magnetic bearing controller in this embodiment are basically the same as those in the embodiments, principles and examples of the aforementioned device, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0125] According to an embodiment of the present invention, a magnetic bearing system corresponding to a fault detection device for a switching power amplifier is also provided. This magnetic bearing system may include: the fault detection device for the switching power amplifier described above, or the magnetic bearing controller described above.

[0126] Since the processing and functions implemented by the magnetic bearing system in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned devices, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0127] According to an embodiment of the present invention, a computer program product corresponding to a fault detection method for a switching power amplifier is also provided, comprising a computer program that, when executed by a processor, implements the steps of the fault detection method for a switching power amplifier described above.

[0128] Since the processing and functions implemented by the product in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0129] According to an embodiment of the present invention, a storage medium corresponding to a fault detection method for a switching power amplifier is also provided. The storage medium includes a stored program, wherein, when the program is executed, the device where the storage medium is located executes the steps of the fault detection method for the switching power amplifier described above.

[0130] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0131] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0132] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method of fault detection for a switching power amplifier, the method comprising: The application can be applied to a magnetic bearing controller; the switching power amplifier comprises an H-bridge, the H-bridge has a first bridge arm and a second bridge arm, the first bridge arm has a first switch tube, and the second bridge arm has a second switch tube; the failure detection method of the switching power amplifier comprises the following steps: During the operation of the switching power amplifier, in the current switching cycle of the switching power amplifier, the current detection value of the first bridge arm is obtained, the current detection value of the second bridge arm is obtained, and the coil current of the magnetic bearing controlled by the magnetic bearing controller is obtained according to a set sampling frequency; According to the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, it is determined whether the switching power amplifier fails, and the failure detection of the switching power amplifier is realized.

2. The method of claim 1, wherein, A first sampling resistance module is arranged between the ground end of the first bridge arm and the ground, a second sampling resistance module is arranged between the ground end of the second bridge arm and the ground, and the resistance value of the first sampling resistance module and the resistance value of the second sampling resistance module are the same as the resistance value of the coil of the magnetic bearing; The current detection value of the first bridge arm is obtained by the following steps: The voltage value obtained by sampling the current detection result of the first bridge arm by the first sampling resistance module is taken as the current detection value of the first bridge arm; The current detection value of the second bridge arm is obtained by the following steps: The voltage value obtained by sampling the current detection result of the second bridge arm by the second sampling resistance module is taken as the current detection value of the second bridge arm.

3. The method of claim 1 or 2, wherein According to the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, it is determined whether the switching power amplifier fails, and the failure detection of the switching power amplifier is realized. The sum of the current detection values of the first bridge arm is determined according to the switching cycle of the switching power amplifier, the set sampling frequency, and the current detection value of the first bridge arm, and is recorded as the total current detection value of the first bridge arm; The sum of the current detection values of the second bridge arm is determined according to the switching cycle of the switching power amplifier, the set sampling frequency, and the current detection value of the second bridge arm, and is recorded as the total current detection value of the second bridge arm; The current threshold value of the switching power amplifier is determined according to the switching cycle of the switching power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller; It is determined whether the total current detection value of the first bridge arm is 0 or the total current detection value of the first bridge arm is the current threshold value of the switching power amplifier, and the total current detection value of the second bridge arm is 0 or the total current detection value of the second bridge arm is the current threshold value of the switching power amplifier; If it is determined that the conditions are met, it is determined that the switching power amplifier fails, and a prompt message of the failure position and / or the failure type of the switching power amplifier is output. If it is determined that the condition is not met, it is determined that the switch power amplifier is not faulty, the switch power amplifier continues to be controlled to operate, and then returns to acquire the current detection value of the first bridge arm, acquire the current detection value of the second bridge arm, and acquire the coil current of the magnetic bearing controlled by the magnetic bearing controller at a set sampling frequency in the next switching cycle of the switch power amplifier.

4. The method of claim 3, wherein the step of detecting a fault in the switching power amplifier comprises the step of: Wherein, According to the switching cycle of the switch power amplifier, the set sampling frequency, and the current detection value of the first bridge arm, the sum of the current detection values of the first bridge arm is determined, which is recorded as the total current detection value of the first bridge arm, including: The product value of the switching cycle of the switch power amplifier, the set sampling frequency, and the current detection value of the first bridge arm is taken as the sum of the current detection values of the first bridge arm, which is recorded as the total current detection value of the first bridge arm; And / or, According to the switching cycle of the switch power amplifier, the set sampling frequency, and the current detection value of the second bridge arm, the sum of the current detection values of the second bridge arm is determined, which is recorded as the total current detection value of the second bridge arm, including: The product value of the switching cycle of the switch power amplifier, the set sampling frequency, and the current detection value of the second bridge arm is taken as the sum of the current detection values of the second bridge arm, which is recorded as the total current detection value of the second bridge arm; And / or, According to the switching cycle of the switch power amplifier, the set sampling frequency, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, the current threshold of the switch power amplifier is determined, including: The product value of the switching cycle of the switch power amplifier, the set sampling frequency, the coil current of the magnetic bearing controlled by the magnetic bearing controller, and the coil resistance of the magnetic bearing controlled by the magnetic bearing controller is taken as the current threshold of the switch power amplifier.

5. The method of claim 3, wherein the step of detecting a fault in the switching power amplifier comprises the step of: If it is determined that the first bridge arm current detection total value is equal to 0, it is determined that the first switch tube is short-circuit faulty, and a prompt message of the fault position of the switch power amplifier being the position of the first switch tube and / or the fault type of the switch power amplifier being short-circuit fault is outputted. If it is determined that the first bridge arm current detection total value is equal to the current threshold of the switch power amplifier, it is determined that the first switch tube is open-circuit faulty, and a prompt message of the fault position of the switch power amplifier being the position of the first switch tube and / or the fault type of the switch power amplifier being open-circuit fault is outputted. If it is determined that the second bridge arm current detection total value is equal to 0, it is determined that the second switch tube is open-circuit faulty, and a prompt message of the fault position of the switch power amplifier being the position of the second switch tube and / or the fault type of the switch power amplifier being open-circuit fault is outputted. ​ If it is determined that the total current detection value of the second bridge arm is equal to the current threshold of the switch power amplifier, it is determined that the second switch tube has a short circuit fault, and a prompt message is outputted that the fault position of the switch power amplifier is the position of the second switch tube and / or the fault type of the switch power amplifier is a short circuit fault.

6. A failure detection apparatus of a switching power amplifier for detecting failure of the switching power amplifier using a failure detection method of the switching power amplifier according to claim 1, characterized by The switch power amplifier can be applied to a magnetic bearing controller, and the switch power amplifier comprises an H-bridge having a first bridge arm and a second bridge arm, the first bridge arm having a first switch tube, and the second bridge arm having a second switch tube. The fault detection device of the switch power amplifier comprises: a first bridge arm current detection unit configured to detect the current of the first bridge arm in each switching cycle of the switch power amplifier; a second bridge arm current detection unit configured to detect the current of the second bridge arm in each switching cycle of the switch power amplifier; 7. A magnetic bearing controller characterized by comprising: a coil current detection unit configured to detect the coil current of the magnetic bearing controlled by the magnetic bearing controller in each switching cycle of the switch power amplifier; a control unit configured to determine whether the switch power amplifier has a fault according to the current detection value of the first bridge arm, the current detection value of the second bridge arm, and the coil current of the magnetic bearing controlled by the magnetic bearing controller, so as to realize fault detection of the switch power amplifier.

8. A magnetic bearing system characterized by, The switch power amplifier comprises: The fault detection device of the switch power amplifier according to claim 6.

9. A storage medium, characterized by The magnetic bearing controller comprises:

10. A computer program product comprising a computer program, characterized in that, The storage medium comprises a stored program, wherein when the program is executed, the device where the storage medium is located executes the fault detection method of the switch power amplifier according to any one of claims 1 to 5. The computer program is executed by a processor to realize the steps of the fault detection method of the switch power amplifier according to any one of claims 1 to 5.

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